JPS6232093Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a control device for an air conditioner for an automobile.

(Prior Art) When an automobile air conditioner is used while idling, the engine rotation speed decreases due to the load required to drive the compressor for compressing refrigerant, which may cause the engine to malfunction, overheat, and even stall. be. As a countermeasure for this, there is a method (first idle) in which the throttle valve's un-driving opening is increased by a certain amount only when the compressor is operating, so that the un-driving rotation speed is the same as the specified idling rotation speed when the compressor is off. It has been considered and is being used.

(Problems to be solved by the invention) However, due to the soaring price of fuel, there is a high demand for improving fuel efficiency, and air conditioners are no exception and there is a great demand for energy saving.

Therefore, in this invention, the driving load of the compressor is reduced by considering that the cooling capacity during idling is kept within the necessary and sufficient range, that is, the cooling capacity above a certain level that does not deteriorate the cooling feeling in the vehicle interior is unnecessary. By controlling the capacity, it can be reduced without increasing the idling speed.
Alternatively, even if it is increased, the purpose is to reduce it compared to the conventional one and contribute to improving fuel efficiency.

(Means for solving the problem) For this purpose, as shown in FIG. 1, in an automotive air conditioner having a compressor 5 which forms a cooling cycle together with an evaporator 3, and an air mix door 12 which divides the air that has passed through the evaporator 3 into that which sends the air to a heater core 4 and that which bypasses the heater core 4, the device is equipped with a revolution speed detector 15 which detects the revolution speed of the engine which drives the compressor 5, compressor control means 42 which controls the amount of adjustment of a capacity varying means 41 which adjusts the discharge capacity of the compressor 5 in accordance with the engine revolution speed detected by the revolution speed detector 15, and air mix door control means 44 which controls the amount of adjustment of an opening adjustment means 43 which adjusts the opening of the air mix door 12 in accordance with the engine revolution speed detected by the revolution speed detector 15, so that when the engine revolution speed is low, the compressor 5 is made to have a low capacity and the air mix door 12 is corrected to the cool side.

(Function) Therefore, the discharge capacity of the compressor 5 is switched depending on the engine rotation speed. For example, if the switching rotation speed is 1000 r.pm, when the rotation speed is 1000 r.pm or less, the capacity of the compressor 5 is changed by the capacity variable means 41. reduced to the desired amount. As a result, the workload of the compressor 5 is reduced and the load on the compressor 5 is reduced, so there is no need to increase the idling speed of the engine due to the air conditioner.
Furthermore, even if it is increased, it can be made smaller than before, contributing to improved fuel efficiency, and achieving the above objective.

(Example) Hereinafter, an example of this invention will be described with reference to the drawings.

In FIG. 2, an embodiment of this invention is shown,
In the automotive air conditioner, inside air or outside air is sucked in from the most upstream side of an air conditioning case 1 by driving a blower 2, and an evaporator 3 and a heater core 4 are provided on the downstream side of the blower 2.

The evaporator 3 constitutes a cooling cycle together with a compressor 5, a condenser 6, a liquid tank 7, and an expansion valve 8, while the heater core 4 is inserted into a hot water cycle in which engine cooling water is circulated. The rotation of the engine is transmitted to the compressor 5 via an electromagnetic clutch 9, and the discharge passage 10a and suction passage 10b of the compressor 5 are short-circuited with a solenoid valve 11 in between. When the valve 11 is closed, all the refrigerant flows into the cooling cycle, but when the solenoid valve 11 is opened, a portion of the discharged refrigerant is returned to the suction side, resulting in a low capacity, and the capacity shown in FIG. This constitutes variable means 41.
In addition to this embodiment, the capacity variable means 41 may be configured to change the number of cylinders of the cooling compressor 5 or change the pulley ratio of the belt transmission device.

In front of the heater core 4, there is an air mix door 1.
The air mix door 12 adjusts the ratio of air passing through the heater core 4 to air bypassing the heater core 4 according to its opening degree, and is operated by an actuator 13. This corresponds to the air mix door opening adjustment means 43 shown in the figure.

Although not shown, the downstream side of the air conditioning case 1 is connected to an upper outlet, a lower outlet, and a defrost outlet.

The microcomputer 14 is a central processing unit.
CPU, memory ROM that stores program procedures and fixed data, memory that can read and write data
It is equipped with RAM, input/output device I/O, and timer.

The microcomputer 14 receives the engine speed from the rotation speed detector 15, the inside temperature from the inside air sensor 16, the outside temperature from the outside air sensor 17, and the set temperature from the temperature setting device 18. The signals of the inside air temperature, outside air temperature, and set temperature are selectively taken in by the multiplexer 19 and sent to the A/D converter 20.
is converted into a digital signal and input. Further, although not shown, on/off signals of operating switches such as a fan switch, mode switch, air conditioner switch, etc. are input to the microcomputer 14.

The microcomputer 14 includes a blower drive circuit 21 that calculates the above-mentioned input signals according to a predetermined program and determines the rotation speed of the blower 2;
An electromagnetic clutch drive circuit 22 for driving the electromagnetic clutch 9 of the compressor 5, a compressor capacity drive circuit 23 for controlling the capacity of the compressor 5,
A control signal is sent to the air mix door drive circuit 24 that controls the air mix door 12, and changes the speed of the blower 2, the opening and closing of the electromagnetic clutch 9, the discharge capacity of the compressor 5, the opening degree of the air mix door 12, and the mode controlled by the mode door (not shown). It is now automatically controlled as appropriate.

In FIG. 3, the microcomputer 1
An example of the control operation according to No. 4 is shown as a flowchart, and the operation will be explained according to this flowchart.

First, calculation is started in a start step 51, and in the next step 52, it is determined whether the engine rotation speed is below a predetermined value.

In this embodiment, the predetermined value is 1000 rpm, and when the rotation speed is higher than the predetermined value, the solenoid valve 11 constituting the capacity variable means remains closed, and the compressor capacity is changed to a high capacity, that is, a normal capacity. The process advances to step 53, where the discharge amount from the compressor becomes the normal amount (ie, the maximum amount). In this case, the process advances to steps 55 and 56, where the number of rotations of the blower and the opening degree of the air mixer door are controlled normally, that is, in accordance with the heat load in the passenger compartment.

If the rotational speed is lower than a predetermined value, the process proceeds to step 54 in which the compressor capacity is reduced to a low capacity, that is, less than the normal capacity, and the solenoid valve 11 is opened and the compressor discharge rate is reduced to 1/2, 2/3, etc. Control is performed to lower the capacity than before. In this case, the process proceeds to step 57, where the rotational speed is set lower than normal, and the process proceeds to step 58, where the air mix door is corrected to the cool side. That is, this prevents the temperature of the blown air from changing as the discharge capacity of the compressor decreases.

(Effects of the invention) As described above, according to this invention, the discharge capacity of the compressor is reduced when the engine speed is in a low rotation range such as when idling.
The driving load of the compressor is reduced,
For this reason, there is no need to set the rotational speed during idling to be high in order to drive the compressor, and even if it is increased, it can be made smaller than in the past, contributing to improved fuel efficiency.

In addition, since the compressor does not stop even in the low rotation range such as when idling, the necessary minimum air conditioning capacity can be obtained, and since the air mix door is corrected to the cool side, the air conditioning feeling will not deteriorate. It is possible to maintain a certain level of air conditioning feeling.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a control device according to this invention, FIG. 2 is a block diagram showing an embodiment of the same, and FIG. 3 is a flowchart showing an example of control operation. 3... Evaporator, 5... Compressor, 1
2... Air mix door, 15... Rotation speed detector, 41... Capacity variable means, 42... Compressor capacity control means, 43... Opening degree adjusting means, 44...
...Air mix door control means.

Claims (1)

[Scope of utility model registration request] An air conditioning system for an automobile has a compressor that constitutes a cooling cycle together with an evaporator, and an air mix door that separates the air that has passed through the evaporator into the air that sends the air to the heater core and the air that bypasses the heater core, the rotation of the engine that drives the compressor. a rotation speed detector for detecting the engine rotation speed; a compressor control means for controlling the adjustment amount of the capacity variable means for adjusting the discharge capacity of the compressor in accordance with the engine rotation speed detected by the rotation speed detector; and air mix door control means for controlling an amount of adjustment of an opening degree adjusting means that adjusts the opening degree of the air mix door according to the engine speed detected by the detector, and when the engine speed is low, the A control device for an air conditioner for an automobile, characterized in that a compressor has a low capacity and the air mix door is corrected to a cool side.